Software to auto-sync an external HD?

I'm using an external (USB) HD to image computers and want to back them up in as painless a way as possible. Is there any software out there that will detect when a drive is plugged in (could be an autorun on the external drive) to a specific machine, and then sync the files with a pre-defined drive or network location? OS is Win7.

If you are willing to use autorun on external drives, this seems pretty straightforward. Just use the autorun.inf to run a script that's stored on the external drive. I'm not sure off hand if this works with scripts or just executables, but clutching together an exe with one of the various script-to-exe tools should work.

If you don't wanna use autorun for e.g. safety reasons, I'd turn to the Windows Event System, which needs setting up things on the host PCs, though.